ci: do not install mingw-w64 in the ordinary ci macos job

.github/workflows/ci.yml

@@ -266,7 +266,6 @@ jobs:
           ##brew install libpq openssl freetype ### these are *already installed* on Catalina ...
           brew uninstall --ignore-dependencies libpq ## libpq is a dependency of PHP
           brew install postgresql
-          brew install mingw-w64
           export LIBRARY_PATH="$LIBRARY_PATH:/usr/local/opt/openssl/lib/"
       - name: Build V
         run: make -j4 && ./v -cg -cflags -Werror -o v cmd/v